A head-on collision closed the Pacific Highway when one vehicle crossed to the wrong side of the road according to Coffs/Clarence Local Area Command.
Before the Toyota Hilux was involved in the two-car collision near Chatsworth Island, the same Hilux was sighted swerving across the road while travelling north near Ulmarra and reported to police.
At about 11.25am on Sunday, the same Toyota Hilux towing a trailer was travelling north on the Pacific Highway at Chatsworth Island when it crossed onto the wrong side of the road, colliding with a Mazda utility.
The 39-year-old man driving the Hilux was trapped in the vehicle for a period of time before he was extricated by the State Emergency Service.
The second male, 28, driving the Mazda was uninjured in the crash.
NSW Ambulance personnel from Maclean and Grafton treated the 39-year-old at the scene before conveying him to the Westpac Helicopter who was waiting nearby.
He was treated for a serious head injury and leg injury by the medical staff on the Westpac Helicopter and was transported to the Gold Coast University Hospital once he was stable.
The highway reopened just after 1.45pm with traffic slowly returning to normal, with the major road closed for an hour and a half while investigations took place.
The collision is being investigated by police in Iluka.